The Daily Grind: Best holiday event of the season

We've only just made it to Christmas Eve here in the real world, but the traditional MMO holiday events have been going strong now for weeks. Like clockwork every year, when December rolls around, we expect our game worlds to be flooded with gift-giving NPCs, have our quest logs filled to capacity with festive tasks, and cop a handful of digital snowballs to the face. This year is no different -- but which MMO was host to the most fun and refreshing holiday event?